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Crystal structure and physical properties of shchurovskyite-related K2CaCu6O2(PO4)4
G V Kiriukhina1,2, O V Yakubovich1, L V Shvanskaya1
1Lomonosov Moscow State University, Moscow 119991, Russia. g-biralo@yandex.ru.
Abstract:
A new oxocuprate phosphate, K2CaCu6O2(PO4)4, was obtained as tabular dark-green single crystals through flux-assisted high-temperature synthesis. It crystallizes in the space group P2/c and represents the centrosymmetric modification of the fumarolic arsenate mineral shchurovskyite, K2CaCu6O2(AsO4)4. The crystal structure of the compound under study is characterized by the presence of large channels filled with potassium cations. Bond-valence energy landscape calculations based on structural data showed the probability of K+ migration through the crystal structure along the b axis at an energy of 0.6 eV. K2CaCu6O2(PO4)4 ordered into a canted antiferromagnetic state in two steps at TN1 = 22 ± 2 K and TN2 = 10 ± 1 K, as revealed by magnetization and specific heat measurements.
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